Discussions By Condition: Repiratory conditions

chest tightness/congested feeling

So for the past few days I've been having this tightness, congested feeling around the left side of my chest. I also feel a little discomfort around that side when I move my upper body. Tuesday night I went to the ER in which I had an x-ray and an ekg and both came back negative. But since then I've had this tightness.feeling around my chest. When I walk or do exercise I don't feel it but when I'm still I feel it. I'm 17 years old, please give me advice.